Sanal Flow Choking Leads to Hemorrhagic Stroke and Other Neurological Disorders in Earth and Human Spaceflight
Evidences are escalating on the diverse neurological disorders associated with COVID-19 pandemic due to the nanoscale Sanal flow choking (PMC7267099). The Sanal flow choking occurs at relatively high and low blood viscosity. Sanal flow choking leads to aneurysm, hemorrhagic-stroke and other neurological-disorders if the vessel geometry is having divergence, bifurcation, stenosis and/or occlusion regions (PMC7933821). Nanoscale Sanal flow choking is more susceptible at microgravity condition due to altered variations of blood viscosity, turbulence and the blood pressure ratio (BPR). Astronauts/Cosmonauts experienced neurological disorders during human spaceflight and thereafter. V.R.S.Kumar et al. (2021) reported that the asymptomatic episodes in the cardiovascular system are due to the internal flow choking (Biofluid/ Sanal flow choking) at a critical blood pressure ratio (BPR), which is regulated by the biofluid/blood heat capacity ratio (BHCR). As the pressure of the nanoscale biofluid / non-continuum-flows rises, fluid viscosity increases and average-mean-free-path diminishes and thus, the Knudsen number lowers heading to a zero-slip wall-boundary condition with the compressible flow regime, which increases the risk of Sanal flow choking and the shock wave generation causing asymptomatic cardiovascular disease. Microgravity environment decreases plasma volume and increases the hematocrit compared with the situation on the Earth surface, which increases the relative viscosity of blood causing an early Sanal flow choking. Herein, we established that the disproportionate blood-thinning treatment increases the risk of the nanoscale Sanal flow choking due to the enhanced boundary-layer-blockage factor. The risk could be diminished by concurrently reducing the viscosity of biofluid/ blood and flow-turbulence by increasing the thermal-tolerance-level in terms of BHCR and/or by decreasing the BPR through new drug discovery or using companion medicine with the traditional blood thinners or other health care management. We recommend all astronauts/cosmonauts should wear ambulatory blood pressure and thermal level monitoring devices similar to a wristwatch throughout the space travel for the diagnosis, prognosis and prevention of internal flow choking leading to asymptomatic cardiovascular disease including neurological disorders.